The change in policy by Denmark very likely comes down to the risk of overloading their ICU's with a naive covid population. When covid first arrived everyone

The change in policy by Denmark very likely comes down to the risk of overloading their ICU's with a naive covid population. When covid first arrived everyone was susceptible to covid and the long tail of poor outcomes was enough to plug up the hospitals (and primarily the ICU's). Now, much of the population has become either naturally or through vaccination much less susceptible to poor outcomes from a covid infection, and this is especially true of younger people. So the response to covid was never really about the health of the population as much as it was about the health of the hospitals. The risk to the hospitals is now much lower and therefore the reasonable vaccination effort has now changed.